As to thermal developing light-sensitive materials with which developing process can be carried out by the thermal treatment, Japanese Patent Examined Publications No. 4921/1968 and No. 4924/1968 have disclosed light-sensitive materials comprising organic silver salts, silver halides and reducing agents.
With the improved thermal developing light-sensitive materials, the studies to obtain color images by various methods have been described.
For example, U.S. Pat. Nos. 3,531,286, 3,761,270 and 3,764,328 have independently disclosed thermal developing color light-sensitive materials respectively forming a dye image by the reaction of an oxidized product of aromatic primary amine developing agents and a coupler.
In addition, Research Disclosure No. 15108 and No. 15127 issues disclosed thermal developing color light-sensitive materials individually forming a dye image by the reaction of an oxidized product of sulfonamidephenol or sulfonamidaniline derivative color developing agent and a coupler. However, these methods incurred a disadvantage; since an image of reduced silver and a dye image are simultaneously formed on an exposed portion after the thermal development, the dye image accompanies stains. To solve this problem, a method is available, wherein a silver image is removed by a liquid treatment, or wherein only dyes are transferred onto other layers, for example, an image-receiving sheet comprising an image-receiving layer. However, such a method incurs still another problem; it is difficult to distinguish unreacted matter from the dyes to be transferred.
Further, Research Disclosure, No. 16966 disclosed a method involving thermal developing color light-sensitive materials, wherein using organic imino silver salts independently having a dye-portion, imino groups on the exposed portion are removed by the thermal development, whereby a dye image is formed on an image-receiving layer as a transfer paper by the use of solvents. However, in this method a problem occurs; it is difficult to suppress the liberation of dyes on unexposed portions, therefore, well-defined clear color images cannot be obtained.
Additionally, Japanese Patent Publication Open to Public Inspection (hereinafter referred to a Japanese Patent O.P.I. Publication) No. 105821/1977, Japanese Patent O.P.I. Publications No. 105822/1977 and No. 50328/1981, U.S. Pat. No. 4,235,957, Research Disclosure No. 14448, No. 15227 and No. 18137 issues disclosed thermal developing color light-sensitive materials for forming a positive color image by a heat-sensitive silver dye bleaching method. However, this method incurs problems: otherwise unnecessary steps to heat piled sheets independently having an activator to accelerate the bleaching of dye, as well as a photographic constituent material; the obtained dye image is eventually reduced and bleached, in the course of a prolonged storage, by the coexisting free silver and the like.
Furthermore, U.S. Patent Nos. 3,180,732, 3,985,565, 4,022,617 and Research Disclosure No. 12533 disclosed thermal developing color light-sensitive materials to form a color image by using a leuco dye. However, this method also incurs a problem; it is difficult to stably contain leuco dye in a photographic light-sensitive material and the photographic light-sensitive material is gradually discolored during its preservation.
Also, Japanese Patent O.P.I. Publications No. 179840/1982, No. 186744/1982, No. 123533/1982, No. 12431/1984, No. 124339/1984, No. 166954/1984, No. 159159/1984, No. 181395/1984, No. 229556/1984, and the like, have disclosed thermal developing coupler light-sensitive materials discharging or forming a diffusible dye by the thermal development to obtain a transferred color image.
However, these prior arts incurs a disadvantage; a larger density (Dmax) causes a increased fogging (Dmin), whereby a restrainer used in a conventional photographic light-sensitive material not only fails to show restraining effects but even deteriorates fogging, or simultaneously deteriorates Dmax as well as the sensitivity. Accordingly, the development of a restrainer usable in the thermal developing light sensitive material has been eagerly desired
The inventor has found that not only the fogging in the thermal development but also the preservability could be simultaneously improved by using a thermal developing light-sensitive material containing a restrainer having a ballast group. However, the degree of the improvement was still insufficient. The inventor also found that if dye-sensitized silver halide emulsions are used, the fogging increases and the sensitivity is reduced during the preservation of the thermal developing light-sensitive materials under a high temperature and a high humidity.
In view of this, the inventors have found that the fogging in the thermal development may be improved by using a thermal developing light-sensitive material containing a restrainer having a hydroxyl group, carboxyl group, sulfon group or sulfin group, or a salt thereof. However, it was learned that this arrangement incurs another disadvantage: the fogging increases during the preservation of the thermal developing light-sensitive material under a high temperature and a high humidity.